If you search on Google for “bourne ultimatum,” the top result is an ad for a contest tied to the movie. For a while, Google didn’t disclose that these Bourne-themed results were ads. (They show up on a different-color background, but it took a while before they were marked as being a “Google Promotion.”)

Is there a danger that search engines will be unfairly biased? Could search engines be bribed? How should we think about the kind of trust that users place in search engines?